U.S. patent application number 14/910490 was filed with the patent office on 2016-09-01 for method and apparatus for controlling adaptive reporting in tdd environment.
This patent application is currently assigned to PANTECH CO., LTD.. The applicant listed for this patent is PANTECH CO., LTD.. Invention is credited to Dong Hyun PARK.
Application Number | 20160255608 14/910490 |
Document ID | / |
Family ID | 52461708 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160255608 |
Kind Code |
A1 |
PARK; Dong Hyun |
September 1, 2016 |
METHOD AND APPARATUS FOR CONTROLLING ADAPTIVE REPORTING IN TDD
ENVIRONMENT
Abstract
A method for enabling a base station to control adaptive
reporting in a TDD environment according to one embodiment of the
present invention comprises the steps of: transmitting, from a base
station to a terminal, an information element including
reporting-setting information comprising reporting cycle and
reporting offset of channel state information; transmitting
information of a UL-DL setting change to the terminal; and
receiving the channel state information by using the reporting
cycle and the reporting offset of the reporting-setting information
corresponding to the changed UL-DL setting.
Inventors: |
PARK; Dong Hyun; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PANTECH CO., LTD. |
Seoul |
|
KR |
|
|
Assignee: |
PANTECH CO., LTD.
Seoul
KR
|
Family ID: |
52461708 |
Appl. No.: |
14/910490 |
Filed: |
August 8, 2014 |
PCT Filed: |
August 8, 2014 |
PCT NO: |
PCT/KR2014/007404 |
371 Date: |
May 10, 2016 |
Current U.S.
Class: |
370/280 |
Current CPC
Class: |
H04L 5/14 20130101; H04L
5/0087 20130101; H04L 5/0096 20130101; H04L 5/0057 20130101; H04W
72/04 20130101; H04L 5/1469 20130101; H04W 72/042 20130101; H04L
5/0053 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04L 5/14 20060101
H04L005/14 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 9, 2013 |
KR |
10-2013-0094942 |
Claims
1. A method for controlling adaptive reporting by a base station in
a Time Division Duplexing (TDD) environment, the method comprising:
transmitting an information element including reporting
configuration information including a reporting periodicity and a
reporting offset of channel status information, from the base
station to a user equipment; transmitting information on an Uplink
(UL)-Downlink (DL) configuration change, from the base station to
the user equipment; and receiving the channel status information by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to the changed
UL-DL configuration, by the base station.
2. The method as claimed in claim 1, wherein the information
element comprises one or more pieces of reporting configuration
information, and one piece of reporting configuration information
corresponds to one UL-DL configuration.
3. The method as claimed in claim 1, wherein the reporting
configuration information is applied to either of a TDD UL-DL
configuration and a DL-reference UL-DL configuration by the base
station.
4. The method as claimed in claim 1, wherein the receiving of the
channel status information comprises determining a DL-reference
UL-DL configuration according to the changed TDD UL-DL
configuration, and receiving the channel status information by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to the
DL-reference UL-DL configuration.
5. The method as claimed in claim 1, wherein the receiving of the
channel status information comprises determining a DL-reference
UL-DL configuration according to TDD UL-DL configurations before
and after the change, and receiving the channel status information
according to reporting configuration information corresponding to
the determined DL-reference UL-DL configuration.
6. A method for controlling adaptive reporting by a user equipment
in a Time Division Duplexing (TDD) environment, the method
comprising: receiving an information element including reporting
configuration information including a reporting periodicity and a
reporting offset of channel status information, from a base station
by the user equipment; receiving information on an Uplink
(UL)-Downlink (DL) configuration change, from the base station by
the user equipment; and transmitting the channel status information
by using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to the changed
UL-DL configuration, by the user equipment.
7. The method as claimed in claim 6, wherein the information
element comprises one or more pieces of T reporting configuration
information, and one piece of reporting configuration information
corresponds to one UL-DL configuration.
8. The method as claimed in claim 6, wherein the reporting
configuration information is applied to either of a TDD UL-DL
configuration and a DL-reference UL-DL configuration by the base
station.
9. The method as claimed in claim 6, wherein the transmitting of
the channel status information comprises determining a DL-reference
UL-DL configuration according to the changed TDD UL-DL
configuration, and transmitting the channel status information by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to the
DL-reference UL-DL configuration.
10. The method as claimed in claim 6, wherein the transmitting of
the channel status information comprises determining a DL-reference
UL-DL configuration according to TDD UL-DL configurations before
and after the change, and transmitting the channel status
information according to the determined reporting configuration
information.
11. A base station for controlling adaptive reporting in a Time
Division Duplexing (TDD) environment, the base station comprising:
a control unit for generating an information element including
reporting configuration information including a reporting
periodicity and a reporting offset of channel status information; a
transmission unit for transmitting the generated information
element to a user equipment, and transmitting, to the user
equipment, information on an Uplink (UL)-Downlink (DL)
configuration change of the user equipment; and a reception unit
for receiving a signal from the user equipment, wherein the control
unit controls the reception unit to receive indicator information
of the user equipment by using a reporting periodicity and a
reporting offset of the reporting configuration information
corresponding to the changed TDD UL-DL configuration.
12. The base station as claimed in claim 11, wherein the
information element comprises one or more pieces of reporting
configuration information, and one piece of reporting configuration
information corresponds to one UL-DL configuration.
13. The base station as claimed in claim 11, wherein the control
unit controls the reception unit to determine a DL-reference UL-DL
configuration according to the changed TDD UL-DL configuration, and
to receive the channel status information by using a reporting
periodicity and a reporting offset of the reporting configuration
information corresponding to the DL-reference UL-DL configuration,
or controls the reception unit to determine a DL-reference UL-DL
configuration according to TDD UL-DL configurations before and
after the change, and to receive the channel status information
according to reporting configuration information corresponding to
the determined DL-reference UL-DL configuration.
14. A user equipment for controlling adaptive reporting in a Time
Division Duplexing (TDD) environment, the user equipment
comprising: a reception unit for receiving, from a base station, an
information element including reporting configuration information
including a reporting periodicity and a reporting offset of channel
status information, and receiving, from the base station,
information on an Uplink (UL)-Downlink (DL) configuration change; a
transmission unit for transmitting a signal to the base station;
and a control unit for controlling the transmission unit to
transmit the channel status information by using a reporting
periodicity and a reporting offset of the reporting configuration
information corresponding to the changed UL-DL configuration.
15. The user equipment as claimed in claim 14, wherein the control
unit controls the transmission unit to determine a DL-reference
UL-DL configuration according to the changed TDD UL-DL
configuration, and to transmit the channel status information by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to the
DL-reference UL-DL configuration, or controls the transmission unit
to determine a DL-reference UL-DL configuration according to TDD
UL-DL configurations before and after the change, and to transmit
the channel status information according to the determined
reporting configuration information.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is the National Stage Entry of
International Application PCT/KR2014/007404, filed on Aug. 8, 2014,
and claims priority from and the benefic of Korea Patent
Application No. 10-2013-0094942, filed on Aug. 9, 2013, which are
hereby incorporated by reference for all purposes as if fully set
forth herein.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates to a method and an apparatus
for controlling adaptive reporting in a Time Division Duplexing
(TDD) environment and, more particularly, to a method and an
apparatus for performing a control operation for adaptively
reporting a periodic Channel Quality Indicator (CQI)/Precoding
Matrix Indicator (PMI).
[0004] 2. Discussion of the Background
[0005] With the progress of communication systems, consumers such
as companies and individuals have used a wide variety of wireless
terminals.
[0006] In current mobile communication systems affiliated with
Third Generation Partnership Project (3GPP), for example, Long Term
Evolution (LTE), LTE-Advanced (LTE-A), and the like, as a
high-speed and high-capacity communication system capable of
transmitting and receiving various data such as images and wireless
data beyond voice-oriented services, it is required to develop a
technology capable of transmitting a large amount of data coming
close to that of a wired communication network. In addition, an
appropriate error detection scheme in which system performance can
be improved by minimizing information loss and increasing system
transmission efficiency, becomes an essential element.
[0007] Also, in many current communication systems, various
Reference Signals (RSs) are used to provide information on a
communication environment and the like to a counterpart apparatus
in uplink or downlink. Further, information for identifying a
status of a channel, or coding information is transmitted at a
predetermined cycle.
SUMMARY
[0008] The present invention proposes a method for performing a
control operation for adaptively reporting a periodic CQI/PMI for
an LTE TDD enhanced Interference Management and Traffic Adaptation
(eIMTA) technique and an apparatus implementing the same.
[0009] An aspect of the present invention is to implement a method
and an apparatus for allowing periodic CQI/PMI reporting, which is
based on a Radio Resource Control (RRC) configuration, to be
achieved with respect to a dynamically-changed TDD Uplink
(UL)-Downlink (DL) configuration (or reconfiguration).
[0010] In accordance with an aspect of the present invention, there
is provided a method for controlling adaptive reporting by a base
station in a TDD environment. The method includes: transmitting an
information element including reporting configuration information
including a reporting periodicity and a reporting offset of channel
status information, from the base station to a user equipment;
transmitting information on an Uplink (UL)-Downlink (DL)
configuration change, from the base station to the user equipment;
and receiving the channel status information by using a reporting
periodicity and a reporting offset of the reporting configuration
information corresponding to the changed UL-DL configuration, by
the base station.
[0011] In accordance with another aspect of the present invention,
there is provided a method for controlling adaptive reporting by a
user equipment in a TDD environment. The method includes: receiving
an information element including reporting configuration
information including a reporting periodicity and a reporting
offset of channel status information, from a base station by the
user equipment; receiving information on an Uplink (UL)-Downlink
(DL) configuration change, from the base station by the user
equipment; and transmitting the channel status information by using
a reporting periodicity and a reporting offset of the reporting
configuration information corresponding to the changed UL-DL
configuration, by the user equipment.
[0012] In accordance with still another aspect of the present
invention, there is provided a base station for controlling
adaptive reporting in a TDD environment. The base station may
include: a control unit for generating an information element
including reporting configuration information including a reporting
periodicity and a reporting offset of channel status information; a
transmission unit for transmitting the generated information
element to a user equipment, and transmitting, to the user
equipment, information on an Uplink (UL)-Downlink (DL)
configuration change of the user equipment; and a reception unit
for receiving a signal from the user equipment, wherein the control
unit may control the reception unit to receive indicator
information of the user equipment by using a reporting periodicity
and a reporting offset of the reporting configuration information
corresponding to the changed TDD UL-DL configuration.
[0013] In accordance with yet another aspect of the present
invention, there is provided a user equipment for controlling
adaptive reporting in a TDD environment. The user equipment
includes: a reception unit for receiving, from a base station, an
information element including reporting configuration information
including a reporting periodicity and a reporting offset of channel
status information, and receiving, from the base station,
information on an Uplink (UL)-Downlink (DL) configuration change; a
transmission unit for transmitting a signal to the base station;
and a control unit for controlling the transmission unit to
transmit the channel status information by using a reporting
periodicity and a reporting offset of the reporting configuration
information corresponding to the changed UL-DL configuration.
[0014] When the present invention is applied, periodic CQI/PMI
reporting, which is based on an RRC configuration, can be performed
according to a dynamically-changed TDD UL-DL configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a view illustrating an eIMTA deployment scenario,
to which the present invention may be applied.
[0016] FIG. 2 is a view illustrating a dynamic TDD UL-DL
configuration.
[0017] FIG. 3 is a view illustrating a case where a reporting
problem arises in the situation of a dynamic TDD UL-DL
configuration.
[0018] FIG. 4 is a view illustrating a case where information
required for reporting is configured when a first method according
to the present invention is applied.
[0019] FIG. 5 is a view illustrating the application of an
embodiment of the present invention.
[0020] FIG. 6 is a view illustrating operations between a base
station and a user equipment according to an embodiment of the
present invention.
[0021] FIG. 7 is a view illustrating a process for controlling
adaptive reporting by a base station in a TDD environment according
to an embodiment of the present invention.
[0022] FIG. 8 is a view illustrating a process for controlling
adaptive reporting by a user equipment in a TDD environment
according to an embodiment of the present invention.
[0023] FIG. 9 is a view illustrating a configuration of a base
station according to an embodiment of the present invention.
[0024] FIG. 10 is a view illustrating a configuration of a user
equipment according to an embodiment of the present invention.
[0025] FIGS. 11 and 12 are views each illustrating a configuration
example of a CQI-ReportPeriodic according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0026] Hereinafter, exemplary embodiments of the present invention
will be described in detail with reference to the exemplary
drawings. In the following description, the same components will be
designated by the same reference numerals although they are shown
in different drawings. Further, in the following description of the
present invention, a detailed description of known functions and
configurations incorporated herein will be omitted when it may make
the subject matter of the present invention rather unclear.
[0027] The wireless communication system may include a User
Equipment (UE) and a Base Station (BS or an eNB). Throughout the
specifications, the user equipment may be an inclusive concept
indicating a user terminal utilized in wireless communication,
including a UE (User Equipment) in WCDMA, LTE, HSPA, and the like,
and an MS (Mobile station), a UT (User Terminal), an SS (Subscriber
Station), a wireless device, and the like in GSM.
[0028] The base station 20 or a cell, may generally refer to a
station where communication with the user equipment 10 is
performed, and may also be referred to as a Node-B, an eNB (evolved
Node-B), a Sector, a Site, a BTS (Base Transceiver System), an
Access Point, a Relay Node, and the like.
[0029] That is, the base station 20 or the cell may be construed as
an inclusive concept indicating a portion of an area covered by a
BSC (Base Station Controller) in CDMA, a NodeB in WCDMA, an eNB or
a sector (site) in LTE, and the like, and the concept may include
various coverage areas, such as a megacell, a macrocell, a
microcell, a picocell, a femtocell, a communication range of a
relay node, and the like.
[0030] In the specification, the user equipment and the base
station are used as two (uplink or downlink) inclusive transceiving
subjects to embody the technology and technical concepts described
in the specifications, and may not be limited to a predetermined
term or word. As used herein, the user equipment may be called a
terminal for short.
[0031] In a system, such as LTE and LTE-A, to which the present
invention may be applied, a standard may be developed by
configuring an uplink and a downlink based on a single carrier or a
pair of carriers. The uplink and the downlink may transmit control
information through a control channel, such as a PDCCH (Physical
Downlink Control CHannel), PCFICH (Physical Control Format
Indicator CHannel), PHICH (Physical Hybrid ARQ Indicator CHannel),
PUCCH (Physical Uplink Control CHannel), and the like, and may be
configured as a data channel, such as PDSCH (Physical Downlink
Shared CHannel), PUSCH (Physical Uplink Shared CHannel), and the
like, so as to transmit data.
[0032] Abbreviations used in this specification are described as
follows.
[0033] PCell: Primary serving cell
[0034] SCell: Secondary serving cell
[0035] RS: Reference Signal
[0036] CRS: Common Reference Signal
[0037] DM-RS: DeModulation Reference Signal
[0038] eIMTA: enhanced Interference Management and Traffic
Adaptation
[0039] CIF: Carrier Indicator Field
[0040] CQI: Channel Quality Indicator
[0041] PMI: Precoding Matrix Indicator
[0042] RI: Rink Inkicator
[0043] In this specification, information or an indicator, which
indicates a channel status of a DL channel such as a CQI/PMI and an
RI, is referred to as "channel status information" or a "channel
information indicator." Also, in this specification, an operation
of a UE for transmitting the channel status information or the
channel information indicator is referred to as "reporting." For
example, an operation of the UE for transmitting a CQI/PMI is
referred to as "CQI/PMI reporting," and an operation of the UE for
transmitting an RI is referred to as "RI reporting."
[0044] Uplink transmission and downlink transmission may be
performed based on a TDD (Time Division Duplex) scheme that
performs transmission based on different times, or based on an FDD
(Frequency Division Duplex) scheme that performs transmission based
on different frequencies. Meanwhile, a timepoint of a downlink and
a timepoint of an uplink may be distinguished in TDD, and when
various TDD configurations exist, timepoints may be varied.
[0045] Table 1 below is a table showing a TDD configuration. It can
be noted that respective UL-DL configurations have different UL-DL
subframe transmission timings.
TABLE-US-00001 TABLE 1 UL-DL configurations Downlink- to-Uplink
Uplink- Switch- downlink point Subframe number configuration
periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D
S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D
D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 5
ms D S U U U D S U U D
[0046] In Table 1, an area indicated by D represents DL and an area
indicated by U represents UL, in a radio frame corresponding to 10
subframes. S represents a special subframe that is switched from a
DL to a UL on the basis of a DL-to-UL switch-point periodicity.
[0047] Table 2 below shows the value of a DL association set index
K in TDD. K has {k.sub.0, k.sub.1, . . . , k.sub.M-1}. Here,
elements of the set K are values used to indicate a DL subframe
corresponding to a UL subframe n-k, as shown in Table 2, and the
number of multiple k values associated with one UL subframe is
defined as M.
TABLE-US-00002 TABLE 2 DL association set index K in TDD: {k.sub.0,
k.sub.1, . . . , k.sub.M-1} UL-DL Subframe n Configuration 0 1 2 3
4 5 6 7 8 9 0 -- -- 6 -- 4 -- -- 6 -- 4 1 -- -- 7, 6 4 -- -- -- 7,
6 4 -- 2 -- -- 8, 7, 4, 6 -- -- -- -- 8, 7, 4, 6 -- -- 3 -- -- 7,
6, 11 6, 5 5, 4 -- -- -- -- -- 4 -- -- 12, 8, 7, 11 6, 5, 4, 7 --
-- -- -- -- -- 5 -- -- 13, 12, 9, 8, 7, 5, 4, 11, 6 -- -- -- -- --
-- -- 6 -- -- 7 7 5 -- -- 7 7 --
[0048] In a UL frame n, response information to a DL signal, DL
information, or the like may be transmitted through a DL subframe
(a subframe n-k) having a subframe number before a k value included
in K. Table 2 signifies a Physical Downlink Shared CHannel (PDSCH)
Acknowledgement/Negative-acknowledgement (Ack/Nack) timing.
[0049] Meanwhile, the setting of a reporting periodicity and a
reporting offset, to which the value of an I.sub.CQI/PMI signaled
via RRC is mapped, follows Table 3 below. An I.sub.CQI/PMI which
indicates the reporting periodicity and the reporting offset is an
example of reporting configuration information. The reporting
configuration information is information indicating a reporting
periodicity and a reporting offset required when the UE reports
CQI/PMI information or RI information to the BS. An I.sub.RI
described below is also an example of the reporting configuration
information.
TABLE-US-00003 TABLE 3 Mapping of I.sub.CQI/PMI to N.sub.pd and
N.sub.OFFSET (CQI of TDD) I.sub.CQI/PMI Value of N.sub.pd Value of
N.sub.OFFSET,CQI I.sub.CQI/PMI = 0 1 I.sub.CQI/PMI 1 .ltoreq.
I.sub.CQI/PMI .ltoreq. 5 5 I.sub.CQI/PMI - 1 6 .ltoreq.
I.sub.CQI/PMI .ltoreq. 15 10 I.sub.CQI/PMI - 6 16 .ltoreq.
I.sub.CQI/PMI .ltoreq. 35 20 I.sub.CQI/PMI - 16 36 .ltoreq.
I.sub.CQI/PMI .ltoreq. 75 40 I.sub.CQI/PMI - 36 76 .ltoreq.
I.sub.CQI/PMI .ltoreq. 155 80 I.sub.CQI/PMI - 76 156 .ltoreq.
I.sub.CQI/PMI .ltoreq. 315 160 I.sub.CQI/PMI - 156 316 .ltoreq.
I.sub.CQI/PMI .ltoreq. 1023 Reserved
[0050] The value of a periodicity to be applied to a serving cell c
for periodic CQI/PMI reporting in TDD is determined according to a
TDD UL-DL configuration of a PCell. When TDD UL-DL configurations
of the PCell are {0, 1, 3, 4, 6}, a reporting periodicity may be
set to be N.sub.pd=1. In this case, the periodicity is equal to 1
ms, and thus, CQI/PMI reporting is performed in all UL
subframes.
[0051] Meanwhile, when TDD UL-DL configurations of the PCell are
{0, 1, 2, 6}, the reporting periodicity may be set to be
N.sub.pd=5. Alternatively, the reporting periodicities may be set
to be N.sub.pd={10, 20, 40, 80, 160} regardless of the TDD UL-DL
configuration of the PCell.
[0052] Mapping values for reporting of Rank Indication (RI) in TDD
follow a report configuration in Table 4 below.
TABLE-US-00004 TABLE 4 Mapping of I.sub.RI to M.sub.RI and
N.sub.OFFSET,RI I.sub.RI Value of M.sub.RI Value of N.sub.OFFSET,RI
0 .ltoreq. I.sub.RI .ltoreq. 160 1 -- I.sub.RI 161 .ltoreq.
I.sub.RI .ltoreq. 321 2 -- (I.sub.RI - 161) 322 .ltoreq. I.sub.RI
.ltoreq. 482 4 -- (I.sub.RI - 322) 483 .ltoreq. I.sub.RI .ltoreq.
643 8 -- (I.sub.RI - 483) 644 .ltoreq. I.sub.RI .ltoreq. 804 16 --
(I.sub.RI - 644) 805 .ltoreq. I.sub.RI .ltoreq. 965 32 -- (I.sub.RI
- 805) 966 .ltoreq. I.sub.RI .ltoreq. 1023 Reserved
[0053] Parameters, that the BS indicates for the above-described
CQI/PMI report and RI report, indicate cqi-pmi-ConfigIndex
(I.sub.CQI/PMI) or ri-ConfigIndex (I.sub.RI) to each serving cell
in the case of TM 1-9 through higher layer signaling, or indicate
cqi-pmi-ConfigIndex (I.sub.CQI/PMI) or ri-ConfigIndex (I.sub.RI) to
each Channel Status Information (CSI)-process of each serving cell
in the case of TM 10 through higher layer signaling. Values of a
CQI/PMI report periodicity N.sub.pd and offset N.sub.OFFSET, CQI,
which enable the identification of a subframe to perform reporting,
are derived by applying the parameters and Table 3. Similarly, the
RI report also indicates values of a periodicity M.sub.RI and a
relative offset N.sub.OFFSET, RI on the basis of the value of
ri-ConfigIndex (I.sub.RI) and Table 4.
[0054] When one or more CSI-subframe sets are configured for the
UE, the CSI-subframe sets are configured as "cqi-pmi-ConfigIndex
and ri-ConfigIndex for subframe set 1" and "cqi-pmi-ConfigIndex2
and ri-ConfigIndex2 for subframe set 2" corresponding to the
respective subframe sets. In addition, in the case of TM 10, the
above-described parameters may be configured in each
CSI-process.
[0055] Relevant reporting instances (i.e., a subframe in which
reporting occurs) according to a reporting mode of the UE derive a
subframe, in which a CQI/PMI or an RI is reported, by using the
Equation below. The following example is an example in a case where
a wideband CQI/PMI is configured. Specifically, a reporting
instance for the wideband CQI/PMI is subframes satisfying Equation
1 below.
(10.times.n.sub.f+.left brkt-bot.n.sub.s/2.right
brkt-bot.-N.sub.OFFSET,CQI)mod(N.sub.pd)=0 [Equation 1]
[0056] When RI reporting is configured, a reporting interval of the
RI reporting is a value obtained by multiplying M.sub.RI by
N.sub.pd, and a reporting instance is subframes satisfying Equation
2 below.
(10.times.n.sub.f+.left brkt-bot.n.sub.s/2.right
brkt-bot.-N.sub.OFFSET,CQI-N.sub.OFFSET,RI)mod(N.sub.pdM.sub.RI)=0
[Equation 2]
[0057] In addition to the above-described Equations, another
Equation may be applied according to another reporting mode.
[0058] Meanwhile, a DL-reference UL-DL configuration according to
TDD UL-DL configurations of a PCell and an SCell for a serving cell
may be configured as in Table 5 below.
TABLE-US-00005 TABLE 5 DL-reference UL-DL configuration according
to UL/DL configurations of PCell and SCell for serving cell
DL-reference (Primary cell UL/DL configuration, UL/DL Set #
Secondary cell UL/DL configuration) configuration Set 1 (0, 0) 0
(1, 0), (1, 1), (1, 6) 1 (2, 0), (2, 2), (2, 1), (2, 6) 2 (3, 0),
(3, 3), (3, 6) 3 (4, 0), (4, 1), (4, 3), (4, 4), (4, 6) 4 (5, 0),
(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6) 5 (6, 0), (6, 6) 6
Set 2 (0, 1), (6, 1) 1 (0, 2), (1, 2), (6, 2) 2 (0, 3), (6, 3) 3
(0, 4), (1, 4), (3, 4), (6, 4) 4 (0, 5), (1, 5), (2, 5), (3, 5),
(4, 5), (6, 5) 5 (0, 6) 6 Set 3 (3, 1), (1, 3) 4 (3, 2), (4, 2),
(2, 3), (2, 4) 5 Set 4 (0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (0,
6) 0 (1, 2), (1, 4), (1, 5) 1 (2, 5) 2 (3, 4), (3, 5) 3 (4, 5) 4
(6, 1), (6, 2), (6, 3), (6, 4), (6, 5) 6 Set 5 (1, 3) 1 (2, 3), (2,
4) 2 (3, 1), (3, 2) 3 (4, 2) 4
[0059] Hereinafter, a TDD UE may signify a terminal that
transmits/receives a signal to TDD.
[0060] i) When Carrier Aggregation (CA) is configured for the TDD
UE and different TDD UL-DL configuration values are set (TDD UL-DL
configuration) for at least two serving cells, a PCell (i.e., a
primary cell) always follows a DL-reference UL-DL configuration
having a value identical to that of a TDD UL-DL configuration of
the PCell.
[0061] ii) When CA is configured for the TDD UE and different TDD
UL-DL configuration values are set for at least two serving
cells,
[0062] ii-1) When the above-described pair (PCell, SCell) belongs
to set 1, a DL HARQ-timing is applied to a DL-reference UL/DL
configuration for an SCell (i.e., a secondary cell), according to a
DL-reference UL-DL configuration for set 1. Set 1 has no limit on a
scheduling method.
[0063] ii-2) Alternatively, when the UE is a terminal supporting
self-scheduling, if a pair belonging to set 2 or set 3 is
configured, the pair follows a DL-reference UL-DL configuration of
set 2 or set 3.
[0064] ii-3) Alternatively, when cross-carrier scheduling is
configured for the UE (i.e., when the UE is configured to monitor a
PDCCH/Enhanced PDCCH (EPDCCH) having a Carrier Indicator Field
(CIF)), if a relevant pair corresponds to set 4 or set 5, the
relevant pair follows a DL-reference UL-DL configuration of set 4
or set 5.
[0065] ii-4) Specifically, when pairs belonging to set 1 satisfy a
UE for which a CIF is configured or is not configured, set 1 uses a
DL-reference UL-DL configuration in the relevant set 1. In
contrast, set 2 and set 3 are applied only for the UE for which the
CIF is not configured, and set 4 and set 5 are applied only for the
UE for which the CIF is configured.
[0066] iii) When CA is configured for the TDD UE and different TDD
UL-DL configuration values are set for at least two serving cells,
if a DL-reference UL-DL configuration for the at least one serving
cell is #5, the UE does not predict that two or more serving cells
will be configured.
[0067] FIG. 1 is a view illustrating an eIMTA deployment scenario,
to which the present invention may be applied.
[0068] Scenario 1 is a scenario in which multiple femtocells are
deployed at an identical carrier frequency. In scenario 2, multiple
femtocells are deployed at an identical carrier frequency, and
multiple macrocells are deployed at an adjacent carrier frequency,
wherein all of the macrocells may have an identical TDD UL-DL
configuration and the femtocells may adjust a TDD UL-DL
configuration. In scenario 3, multiple femtocells are deployed at
an identical carrier frequency, and are located in outdoor areas.
In scenario 4, multiple outdoor picocells are deployed at an
identical carrier frequency, and multiple macrocells are deployed
at multiple adjacent carrier frequencies, wherein all of the
macrocells may have an identical TDD UL-DL configuration and the
outdoor picocells may adjust a TDD UL-DL configuration.
Accordingly, small cells (e.g., picocells or femtocells) except for
the macrocells are capable of changing a dynamic TDD UL-DL
configuration.
[0069] Hereinafter, a description will be made of a scheme in which
reporting configuration information, which may be applied between a
relevant BS and a relevant UE, is applied to a dynamic TDD UL-DL in
a network (a network environment to which a dynamic TDD UL-DL
configuration or reconfiguration is applied) in which eIMTA is
configured according to an embodiment of the present invention.
Reporting information, to which the reporting configuration
information is to be applied, may be a CQI/PMI or an RI. The
reporting configuration information may be identically applied to a
CQI/PMI or an RI. A method and an apparatus for adaptively
performing periodic CQI/PMI or RI reporting will be described.
[0070] FIG. 2 is a view illustrating a dynamic TDD UL-DL
configuration.
[0071] FIG. 2 illustrates that a TDD UL-DL configuration for an
eIMTA capable UE may be quickly changed as represented by #0, #1,
and #2 in a unit of tens of milliseconds according to signaling by
an eNB. However, it is problematic to intactly utilize an existing
reporting method in an environment illustrated in FIG. 2. This
configuration will be described with reference to FIG. 3.
[0072] FIG. 3 is a view illustrating a case where a reporting
problem arises in the situation of a dynamic TDD UL-DL
configuration.
[0073] When the above-described method for periodic CQI/PMI
reporting (TDD) is intactly applied to eIMTA (i.e., a dynamic TDD
UL-DL configuration change), a case occurs in which periodic
CQI/PMI reporting is not capable of being performed according to a
particular TDD UL-DL configuration. A radio frame n indicated by
reference numeral 310 of FIG. 3 has a TDD UL-DL configuration of 0,
and reporting configuration information I.sub.CQI/PMI to be applied
to the radio frame n is set to have 0. I.sub.CQI/PMI=0 signifies a
case where N.sub.pd is equal to 1 and N.sub.OFFSET, CQI is equal to
0. The reporting configuration information may be set to RRC. When,
after the radio frame n, a radio frame n+1 is dynamically changed
to a TDD UL-DL configuration #2 as indicated by reference numeral
320, periodic CQI/PMI reporting may not be performed. Specifically,
the TDD UL-DL configurations are different before and after a
changing boundary between the radio frame n indicated by reference
numeral 310 and the radio frame n+1 indicated by reference numeral
320. Accordingly, when reporting configuration information
identical to that of the radio frame (the radio frame 310) before
the boundary is applied to the radio frame 320, the radio frame 320
is different from the radio frame 310 with respect to a UL-DL
subframe configuration within a radio frame, and thus, reporting
may not be properly performed, so that there is a need for a
solution thereto.
[0074] Hereinafter, a description will be made of first and second
methods for performing periodic reporting when a TDD UL-DL
configuration is dynamically changed. Changing of the TDD UL-DL
configuration may include changing, by a BS, a TDD UL-DL
configuration of a cell; and indicating, by the BS, the changing of
the TDD UL-DL configuration to a UE, and the UE may change the TDD
UL-DL configuration according to the indication from the BS or at a
pre-agreed time point. Hereinafter, the changing of the TDD UL-DL
configuration includes all of the processes.
[0075] A first method: a method for previously configuring
information required for reporting so as to be applicable to each
TDD UL-DL configuration.
[0076] It is possible to previously configure and use CQI/PMI
reporting information applicable to each TDD UL-DL configuration or
each TDD UL-DL configuration set. A particular reporting indicator
I_CQI/PMI may be mapped to each TDD UL-DL configuration or each TDD
UL-DL configuration set. CQI/PMI reporting information may include
information on a CQI/PMI reporting periodicity and a CQI/PMI
reporting offset. The previously-configured information may be
shared (higher layer signaling) by the BS and the UE, and when the
BS changes a TDD UL-DL configuration, the UE may use reporting
information corresponding to the changed TDD UL-DL configuration.
When the TDD UL-DL configuration is changed, the UE may perform
periodic CQI/PMI reporting on the basis of reporting information
corresponding to a reporting indicator mapped to the changed TDD
UL-DL configuration.
[0077] A first method may indicate values of
I.sub.CQI/PMI.sub._.sub.i (N.sub.pd.sub._.sub.i, N.sub.OFFSET,
CQI.sub._.sub.1), which is reporting configuration information that
a TDD UL-DL configuration capable of being configured for an eIMTA
capable UE may apply, to each TDD UL-DL configuration or each set
of TDD UL-DL configurations. Here, the value of i may be equal to 7
which is the number of all of the current TDD UL-DL configurations,
or less. Also, as the number of TDD UL-DL configurations increases,
the value of i may increase. Therefore, the values of
I.sub.CQI/PMI.sub._.sub.i which is multiple pieces of reporting
configuration information may be indicated to the eIMTA capable UE
for periodic CQI/PMI reporting. It is possible to dynamically
change periodic CQI/PMI reporting suitable for an actual TDD UL-DL
configuration, which is dynamically changed, through the indicated
values of I.sub.CQI/PMI.sub._.sub.i. The dynamic TDD UL-DL
configuration change is capable of being applied through a PDCCH or
an EPDCCH.
[0078] For example, multiple pieces of I.sub.CQI/PMI, which are
capable of being configured for each of all available TDD UL-DL
configurations, may be signaled to one eIMTA capable UE.
[0079] A periodicity of periodic CQI/PMI reporting is set by the BS
on the basis of the scheme. An example of reporting configuration
information to be configured according to TDD UL-DL will be
described below.
[0080] When the BS changes the TDD UL-DL configuration, the UE
connected to the relevant BS previously has the reporting
configuration information which is matched to the changed TDD UL-DL
configuration, and thus, the UE may adaptively apply the reporting
configuration information to the change of a TDD UL-DL in a
cell.
[0081] When a TDD UL-DL configuration is {0, 3, 4}, reporting
configuration information may be configured as
I.sub.CQI/PMI.sub._.sub.0=0 (N.sub.pd.sub._.sub.0=1, N.sub.OFFSET,
CQI.sub._.sub.0=0). In this case, a CQI/PMI reporting indicator,
namely, reporting configuration information, may be mapped to 0
with respect to {0, 3, 4} which is a set of TDD UL-DL configuration
values. Here, each number of {0, 3, 4} signifies a TDD UL-DL
configuration value. A CQI/PMI reporting periodicity and a CQI/PMI
reporting offset may be configured to respectively have 1 and 0 for
the UE on the basis of the mapped CQI/PMI reporting indicator
0.
[0082] Specifically, when the TDD UL-DL configuration is changed to
one configuration value of {0, 3, 4} according to an indication
from the BS, the UE performs periodic CQI/PMI reporting which is
based on the CQI/PMI reporting indicator 0.
[0083] When a TDD UL-DL configuration is {1, 2}, reporting
configuration information may be configured as
1.ltoreq.I.sub.CQI/PMI.sub._.sub.1.ltoreq.5(N.sub.pd.sub._.sub.1=5,
I.sub.CQI/PMI.sub._.sub.1-1), and one of values within the range
may be designated and the relevant value may be used as reporting
configuration information. In this configuration, a CQI/PMI
reporting indicator, namely, reporting configuration information,
is set to one of values of 1 to 5 with respect to {1, 2} which is a
set of TDD UL-DL configuration values, and the value is previously
signaled by using a higher layer. For example, the reporting
configuration information may be set to a value of 1. When the TDD
UL-DL configuration is changed according to an indication from the
BS, if the TDD UL-DL configuration is the values of {1, 2}, the UE
may perform reporting by applying "1" which is the signaled
reporting configuration information. When a CQI/PMI reporting
indicator is applied which is an example of the reporting
configuration information, a periodicity is equal to 5 and an
offset is equal to 0.
[0084] When a TDD UL-DL configuration is {5, 6}, reporting
configuration information may be configured as
16.ltoreq.I.sub.CQI/PMI.sub._.sub.2.ltoreq.35(N.sub.pd.sub._.sub.2=20,
I.sub.CQI/PMI.sub._.sub.2-16), and one of values within the range
may be designated and the relevant value may be used as reporting
configuration information. Similarly, when the value of the TDD
UL-DL configuration is equal to 5 or 6, reporting configuration
information, that the UE is to use, may be set to one (e.g., 20) of
values of 16 to 35 by the BS, and may be indicated through higher
layer signaling. In this case, when the TDD UL-DL configuration is
5 or 6 according to an indication from the BS, the UE may perform
CQI/PMI reporting by applying the reporting configuration
information of 20 and by using a periodicity of 20 and an offset of
4.
[0085] FIG. 4 is a view illustrating a case where information
required for reporting is configured when the first method
according to the present invention is applied. When wideband
CQI/PMI reporting is configured, a reporting instance occurs in a
UL subframe satisfying (10.times.n.sub.f+.left
brkt-bot.n.sub.s/2.right brkt-bot.-N.sub.OFFSET,CQI)mod(N.sub.pd)=0
which is Equation 1.
[0086] Referring to FIG. 4, a radio frame indicated by reference
numeral 410 has a TDD UL-DL configuration of 0, and thus, a
reporting mode is set to I.sub.CQI/PMI=0 (N.sub.pd=1,
N.sub.OFFSET,CQI=0). A radio frame indicated by reference numeral
420 has a TDD UL-DL configuration of 2, and thus, a reporting mode
is set to I.sub.CQI/PMI=3 (N.sub.pd.sub._.sub.1=5,
N.sub.OFFSET,CQI=2). When the BS maintains the TDD UL-DL
configuration to be 0 and changes the TDD UL-DL configuration to 2,
the UE performs reporting by applying 0 and 3 which are two pieces
of reporting configuration information respectively corresponding
to the TDD UL-DL configuration of 0 and the TDD UL-DL configuration
of 2.
[0087] Sets of the TDD UL-DL configuration values may be variously
configured within an available range.
[0088] A second method: configures TDD based on a DL reference
timing.
[0089] A DL reference timing may be applied in order to perform a
continuous DL/UL HARQ operation during a dynamic TDD configuration,
and I.sub.CQI/PMI capable of supporting periodic CQI/PMI reporting
may be indicated based on the DL reference timing.
[0090] More specifically, another periodic CQI/PMI reporting method
may be considered according to a method of how to indicate a timing
with a DL reference timing as a reference. In the present
invention, the DL reference timing is considered as a reference,
but the present invention is not limited thereto.
[0091] 2-1 Case: A DL-Reference UL-DL Configuration by Higher Layer
Signaling
[0092] In this case, a DL HARQ operation is performed according to
a DL reference timing, which has been set by a higher layer,
regardless of a change of an actual TDD UL-DL configuration. It
goes without saying that a DL reference timing, which is suitable
for an actual TDD UL-DL configuration, may be set and the BS may
determine a DL reference timing, which is desired to be set,
through a separate process. Also, here, there are two different
application ranges. Firstly, i) a configured DL-reference UL-DL
configuration may be applied to all subframes, or secondly, ii) a
DL-reference UL-DL configuration may be applied to only boundary
radio frames in which a TDD UL-DL configuration is changed.
[0093] A BS indicates, to an eIMTA capable UE, additional reporting
configuration information (e.g., the value of I.sub.CQI/PMI), which
is based on a DL-reference UL-DL configuration required for an
eIMTA operation, together with the DL-reference UL-DL
configuration. Accordingly, the BS determines the value of
N.sub.pd, which is applicable according to a TDD UL-DL
configuration in the current standards, on the basis of a
DL-reference UL-DL configuration, and indicates the value of
I.sub.CQI/PMI, which corresponds to the determined value of
N.sub.pd, to the eIMTA capable UE. Another example of the reporting
configuration information may also include I.sub.RI, and the two
types of indication values may be configured within one information
element.
[0094] FIG. 5 is a view illustrating the application of an
embodiment of the present invention.
[0095] FIG. 5 illustrates an example of a case to which i) a
DL-reference UL-DL configuration, that a higher layer signals, is
applied to all of the subframes in the 2-1 case. FIG. 5 illustrates
a reporting time period (boundary radio frames) to which a
DL-reference UL-DL configuration #2, that the higher layer
configures, may be applied. 3 (which corresponds to N.sub.pd=5),
which is the value of additionally-indicated I.sub.CQI/PMI which is
based on the configured DL-reference UL-DL configuration, is
applied to the boundary radio frames. As another example, a
relevant DL-reference UL-DL configuration and I.sub.CQI/PMI
(N.sub.pd=5) may be applied to only the boundary radio frames
indicated by reference numeral 510.
[0096] Although a DL-reference UL-DL configuration is considered as
a reference indicating the above-described value of in this regard,
the value of I.sub.CQI/PMI may be set with subframes all having a
common UL subframe as a reference.
[0097] 2-2 Case: A DL-Reference UL-DL Configuration According to an
Implicit or Fixed Scheme
[0098] In this case, a method is provided for selecting a
DL-reference UL-DL configuration which is applicable according to a
change of an actual TDD UL-DL configuration. The method is a scheme
for selecting a DL DL-UL reference timing, which may be applied to
an SCell, according to TDD UL-DL configurations of a PCell and an
SCell, and in eIMTA, enables an appropriate DL-reference UL-DL
configuration to be selected according to TDD UL-DL configurations
before and after a boundary radio frame, in which an actual TDD
UL-DL configuration is changed, in the boundary radio frame.
Accordingly, in the 2-2 case, the selected DL-reference UL-DL
configuration may be applied to only a boundary radio frame.
[0099] In the 2-2 case, the above-described first method may be
applied. The application of the second method and that of the first
method in the 2-2 case are only different from each other with
respect to the position of a subframe to which a DL-reference UL-DL
configuration is applied, and there is no difference between the
application of the second method and that of the first method in
the 2-2 case.
[0100] In order to perform reporting by using the second method,
the UE may operate as follows.
[0101] The value of a periodicity, which is to be applied to a
serving cell c for periodic CQI/PMI reporting in TDD, may be
determined according to a DL-reference UL-DL configuration of a
PCell. When DL-reference UL-DL configurations of the PCell are {0,
1, 3, 4, 6}, a reporting periodicity may be set to be N.sub.pd=1.
In this case, the reporting periodicity is equal to 1 ms, and thus,
CQI/PMI reporting is performed in all of the UL subframes.
[0102] Meanwhile, when DL-reference UL-DL configurations of the
PCell are {0, 1, 2 6}, the reporting periodicity may be set to be
N.sub.pd=5. Alternatively, the reporting periodicities may be set
to be N.sub.pd={10, 20, 40, 80, 160} regardless of the DL-reference
UL-DL configuration of the PCell.
[0103] Table 6 below describes a configuration of
CQI-ReportPeriodic of CQI-ReportConfig information elements
required to indicate I.sub.CQI/PMI and I.sub.RI in the case of RRC
signaling as an embodiment for implementing the present
invention.
TABLE-US-00006 TABLE 6 Configuration of CQI-ReportPeriodic
CQI-ReportPeriodic ::= CHOICE { release NULL, setup SEQUENCE {
cqi-PUCCH-ResourceIndex INTEGER (0..1165), cqi-pmi-ConfigIndex
INTEGER (0..1023), cqi-FormatIndicatorPeriodic CHOICE { widebandCQI
NULL, subbandCQI SEQUENCE { k INTEGER (1..4) } }, ri-ConfigIndex
INTEGER (0..1023) OPTIONAL, -- Need OR simultaneousAckNackAndCQI
BOOLEAN } }
[0104] cqi-pmi-ConfigIndex is a parameter which indicates
I.sub.CQI/PMI, and ri-ConfigIndex is a parameter which indicates
I.sub.RI. CQI-ReportPeriodic, which includes the two parameters,
represents RRC signaling, and multiple RRC signalings may be
configured for each carrier. Multiple values of
I.sub.CQI/PMI.sub._.sub.i (0<i<7) may indicate values
corresponding to all TDD UL-DL configurations.
[0105] FIG. 6 is a view illustrating operations between a BS and a
UE according to an embodiment of the present invention. Referring
to FIG. 6, in step S630, the eNB 610, which is a BS, transmits
eIMTA higher layer configuration information to the UE 620. The
configuration information includes a DL or UL-reference UL-DL
configuration and reporting configuration information. The
reporting configuration information includes CQI/PMI reporting
configuration information and/or RI reporting configuration
information. At this time, the UL-DL configuration may include
applicable reporting configuration information, and multiple UL-DL
configurations may also include one applicable piece of reporting
configuration information, as described above. Alternatively,
DL-reference UL-DL reporting configuration information, which is
not a TDD UL-DL configuration, may be included, and in this regard,
the above-described DL-reference UL-DL configuration also
corresponds to a TDD UL-DL configuration. Accordingly, a scheme for
transmitting the reporting configuration information may be
implemented as in the case of a TDD UL-DL configuration.
[0106] In step S640, the UE 620 identifies and applies the
configuration provided by the eNB 610. At this time, the UE 620
applies periodic CQI/PMI reporting or periodic RI reporting by
applying an embodiment of the present invention. In this regard,
the UE 620 may apply pieces of reporting configuration information
corresponding to all of the TDD UL-DL configurations as in the
above-described first method, or may apply reporting configuration
information corresponding to a DL-reference UL-DL configuration as
in the second method.
[0107] Thereafter, in steps S650 and S660, the eNB 610 indicates,
to the UE 620, a change of a TDD UL-DL configuration by using
physical layer signaling. In steps S655 and S665, the UE 620
performs reporting by applying a reporting periodicity and a
reporting offset, which correspond to the relevant reporting
configuration information, according to the change.
[0108] The UE 620 may apply reporting configuration information
corresponding to the TDD UL-DL configuration as in the
above-described first method, or may identify a DL-reference UL-DL
configuration by using the TDD UL-DL configuration and may apply
reporting configuration information corresponding to the identified
DL-reference UL-DL configuration, as in the second method. In the
case of the second method, the UE 620 may apply the reporting
configuration information to all of the TDD UL-DL configurations,
or may apply the reporting configuration information to boundary
radio frames in which a UL-DL configuration is changed.
[0109] FIG. 7 is a view illustrating a process for controlling
adaptive reporting by a BS in a TDD environment according to an
embodiment of the present invention.
[0110] In step S710, the BS generates an information element
including reporting configuration information to be applied to
either of a TDD UL-DL configuration and a DL-reference UL-DL
configuration. Next, in S720, the BS transmits the generated
information element through higher layer signaling. In step S730,
after the TDD UL-DL configuration is changed, the BS receives
reporting from the UE by using a reporting periodicity and a
reporting offset of the reporting configuration information
corresponding to the changed TDD UL-DL configuration. Both the
reporting configuration information corresponding to the TDD UL-DL
configuration and reporting configuration information corresponding
to a DL-reference UL-DL configuration derived from the TDD UL-DL
configuration may be applied as embodiments of the present
invention.
[0111] The change may be performed according to an indication from
the BS, or may be performed according to an indication from another
BS, a Remote Radio Head (RRH), or the like that is controlled by
the BS or cooperates with the BS. Alternatively, the change may be
performed without a separate indication at a time point which is
agreed upon with the UE so as to have predetermined time intervals.
The examples of the change are not limited to the description.
[0112] More specifically, in order to implement the above-described
first method as an embodiment of the present invention, the
information element includes one or more pieces of reporting
configuration information to be applied to one or more TDD UL-DL
configurations. That is, one piece of reporting configuration
information, which is applicable to one or more TDD UL-DL
configurations, may exist, and the multiple pieces of reporting
configuration information may exist in association with the number
of multiple TDD UL-DL configurations. For example, I.sub.CQI/PMI
.sub._.sub.i or I.sub.RI.sub._.sub.i, which is one piece of
reporting configuration information, may be configured for each TDD
UL-DL configuration represented by i, a UL-DL configuration may be
configured as a set represented by i, and I.sub.CQI/PMI
.sub._.sub.i or I.sub.RI.sub._.sub.i may be configured which is
reporting configuration information applied to the set i.
[0113] Meanwhile, in the second method, reporting configuration
information may be reporting configuration information applied to a
DL-reference UL-DL configuration. In this case, reception step S730
may be implemented such that the BS receives reporting from the UE
by using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to a DL-reference
UL-DL configuration identified based on the TDD UL-DL
configuration. For example, when a UL-DL configuration of an SCell
is 2, a UL-DL configuration of a PCell is 2, and the UL-DL
configuration of the SCell and that of the PCell correspond to set
1, if Table 5 is applied, a DL-reference UL-DL configuration is 2.
The BS receives reporting from the UE by using a reporting
periodicity and a reporting offset which are indicated by
I.sub.CQI/PMI or I.sub.RI which is reporting configuration
information corresponding to a configuration of 2.
[0114] A method which uses the reporting configuration information
of the DL-reference UL-DL configuration may be applied to all of
the radio frames or may be applied to only a boundary radio frame,
as described above with reference to FIG. 5. In this case, in
reception step S730, the BS may receive reporting from the UE by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to a DL-reference
UL-DL configuration identified based on the TDD UL-DL configuration
in the boundary radio frame.
[0115] Also, a DL-reference UL-DL configuration may be selected
according to the implicit or fixed scheme as described in the 2-2
case. In this case, in reception step S730, the BS receives
reporting from the UE according to reporting configuration
information determined according to TDD UL-DL configurations before
and after the change. The determined reporting configuration
information is configured according to the implicit or fixed scheme
between the BS and the UE, and thus a DL-reference UL-DL
configuration, to which the reporting configuration information is
to be applied, may be predetermined in a network design process, or
may be predetermined in such a manner that the BS possesses various
selection items and signals a particular selection item to UEs.
[0116] FIG. 8 is a view illustrating a process for controlling
adaptive reporting by a UE in a TDD environment according to an
embodiment of the present invention.
[0117] In step S810, the UE receives an information element, which
includes reporting configuration information to be applied to
either of a TDD UL-DL configuration and a DL-reference UL-DL
configuration, from the BS through higher layer signaling. Then,
after the TDD UL-DL configuration is changed according to a
previously-agreed scheme in step S820, in step S830, the UE
transmits reporting by using a reporting periodicity and a
reporting offset of the reporting configuration information related
to a DL-reference UL-DL configuration corresponding to the changed
TDD UL-DL configuration or the changed TDD UL-DL. Both the
reporting configuration information corresponding to the TDD UL-DL
configuration and reporting configuration information corresponding
to a DL-reference UL-DL configuration derived from the TDD UL-DL
configuration may be applied as embodiments of the present
invention.
[0118] The change may be performed according to an indication from
the BS, or may be performed according to an indication from another
BS, an RRH, or the like that is controlled by the BS or cooperates
with the BS. Alternatively, the change may be performed without a
separate indication at a time point which is agreed upon with the
BS so as to have predetermined time intervals. The examples of the
change are not limited to the description.
[0119] More specifically, in order to implement the above-described
first method as an embodiment of the present invention, the
information element includes one or more pieces of reporting
configuration information to be applied to one or more UL-DL
configurations. That is, one piece of reporting configuration
information, which is applicable to one or more TDD UL-DL
configurations, may exist, and the multiple pieces of reporting
configuration information may exist in association with the number
of multiple TDD UL-DL configurations. For example,
I.sub.CQI/PMI.sub._.sub.i or I.sub.RI.sub._.sub.i, which is one
piece of reporting configuration information, may be configured for
each TDD UL-DL configuration represented by i, a TDD UL-DL
configuration may be configured as a set represented by i, and
I.sub.CQI/PMI .sub._.sub.i or I.sub.RI.sub._.sub.i may be
configured which is reporting configuration information applied to
the set i.
[0120] Meanwhile, in the second method, reporting configuration
information may be reporting configuration information applied to a
DL-reference UL-DL configuration. In this case, transmission step
S830 may be implemented such that the UE transmits reporting by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to a DL-reference
UL-DL configuration identified based on the TDD UL-DL
configuration. For example, when a TDD UL-DL configuration of an
SCell is 2, a TDD UL-DL configuration of a PCell is 2, and the
UL-DL configuration of the SCell and that of the PCell correspond
to set 1, if Table 5 is applied, a DL-reference UL-DL configuration
is 2. The UE transmits reporting by using a reporting periodicity
and a reporting offset which are indicated by I.sub.CQI/PMI or
I.sub.RI which is reporting configuration information corresponding
to a configuration of 2.
[0121] A method which uses the reporting configuration information
of the DL-reference UL-DL configuration may be applied to all of
the subframes or may be applied to only subframes within a boundary
radio frame, as described above with reference to FIG. 5. In this
case, in transmission step S830, the UE may transmit reporting by
using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to a DL-reference
UL-DL configuration identified based on the TDD UL-DL configuration
in the boundary subframes.
[0122] Also, a DL-reference UL-DL configuration may be selected
according to the implicit or fixed scheme as described in the 2-2
case. In this case, in transmission step S830, the UE transmits
reporting according to reporting configuration information
determined according to TDD UL-DL configurations before and after
the change. The determined reporting configuration information is
configured according to the implicit or fixed scheme between the BS
and the UE, and thus a DL-reference UL-DL configuration, to which
the reporting configuration information is to be applied, may be
predetermined in a network design process, or may be predetermined
in such a manner that the BS possesses various selection items and
signals a particular selection item to UEs.
[0123] FIG. 9 is a view illustrating a configuration of a BS
according to an embodiment of the present invention.
[0124] The configuration of the BS 900 is described. The BS 900
includes a control unit 920, a reception unit 910, and a
transmission unit 930. The control unit 920 generates an
information element which includes reporting configuration
information to be applied to either of a TDD UL-DL configuration
and a DL-reference UL-DL configuration, and the transmission unit
930 transmits the generated information element through higher
layer signaling. The reception unit 910 receives a signal from the
UE. After the control unit 920 changes the TDD UL-DL configuration,
the control unit 920 may control the reception unit 910 to receive
reporting from the UE by using a reporting periodicity and a
reporting offset of the reporting configuration information
corresponding to the changed TDD UL-DL configuration, and enables
the BS to control adaptive reporting in a TDD environment. Both the
reporting configuration information corresponding to the TDD UL-DL
configuration and reporting configuration information corresponding
to a DL-reference UL-DL configuration derived from the TDD UL-DL
configuration may be applied as embodiments of the present
invention.
[0125] The change of the TDD UL-DL configuration may be performed
according to an indication from the BS, or may be performed
according to an indication from another BS, an RRH, or the like
that is controlled by the BS or cooperates with the BS.
Alternatively, the change may be performed without a separate
indication at a time point which is agreed upon with the UE so as
to have predetermined time intervals. The examples of the change
are not limited to the description.
[0126] More specifically, in order to implement the above-described
first method as an embodiment of the present invention, the
information element includes one or more pieces of reporting
configuration information to be applied to one or more TDD UL-DL
configurations. That is, one piece of reporting configuration
information, which is applicable to one or more UL-DL
configurations, may exist, and the multiple pieces of reporting
configuration information may exist in association with the number
of multiple TDD UL-DL configurations. For example, I.sub.CQI/PMI
.sub._.sub.i or I.sub.RI.sub._.sub.i, which is one piece of
reporting configuration information, may be configured for each TDD
UL-DL configuration represented by i, a TDD UL-DL configuration may
be configured as a set represented by i, and I.sub.CQI/PMI
.sub._.sub.i or I.sub.RI.sub._.sub.i may be configured which is
reporting configuration information applied to the set i.
[0127] Meanwhile, in the second method, reporting configuration
information may be reporting configuration information applied to a
DL-reference UL-DL configuration. In this case, the control unit
920 may control the reception unit to receive reporting from the UE
by using a reporting periodicity and a reporting offset of the
reporting configuration information corresponding to a DL-reference
UL-DL configuration identified based on the TDD UL-DL
configuration. For example, when a TDD UL-DL configuration of an
SCell is 2, a UL-DL configuration of a PCell is 2, and the UL-DL
configuration of the SCell and that of the PCell correspond to set
1, if Table 5 is applied, a DL-reference UL-DL configuration is 2.
The BS receives reporting from the UE by using a reporting
periodicity and a reporting offset which are indicated by
I.sub.CQI/PMI or I.sub.RI which is reporting configuration
information corresponding to a configuration of 2.
[0128] A method which uses the reporting configuration information
of the DL-reference UL-DL configuration may be applied to all of
the radio frames or may be applied to only a boundary radio frame,
as described above with reference to FIG. 5. In this case, the
control unit 920 may control the reception unit to receive
reporting from the UE by using a reporting periodicity and a
reporting offset of the reporting configuration information
corresponding to a DL-reference UL-DL configuration identified
based on the TDD UL-DL configuration in the boundary radio
frame.
[0129] Also, a DL-reference UL-DL configuration may be selected
according to the implicit or fixed scheme as described in the 2-2
case. In this case, the control unit 920 controls the reception
unit to receive reporting from the UE according to reporting
configuration information determined according to TDD UL-DL
configurations before and after the change. The determined
reporting configuration information is configured according to the
implicit or fixed scheme between the BS and the UE, and thus a
DL-reference UL-DL configuration, to which the reporting
configuration information is to be applied, may be predetermined in
a network design process, or may be predetermined in such a manner
that the BS possesses various selection items and signals a
particular selection item to UEs.
[0130] FIG. 10 is a view illustrating a configuration of a UE
according to an embodiment of the present invention. The
configuration of the UE 1000 is described. The UE 1000 includes a
control unit 1020, a reception unit 1010, and a transmission unit
1030. More specifically, the reception unit 1010 of the UE receives
an information element, which includes reporting configuration
information to be applied to either of a TDD UL-DL configuration
and a DL-reference UL-DL configuration, from the BS through higher
layer signaling. The transmission unit 1030 transmits a signal to
the BS. After the TDD UL-DL configuration is changed according to a
previously-agreed scheme, the control unit 1020 controls the
transmission unit 1030 to transmit reporting by using a reporting
periodicity and a reporting offset of the reporting configuration
information corresponding to the changed TDD UL-DL configuration.
Both the reporting configuration information corresponding to the
TDD UL-DL configuration and reporting configuration information
corresponding to a DL-reference UL-DL configuration derived from
the TDD UL-DL configuration may be applied as embodiments of the
present invention.
[0131] The change of the TDD UL-DL configuration may be performed
according to an indication from the BS, or may be performed
according to an indication from another BS, an RRH, or the like
that is controlled by the BS or cooperates with the BS.
Alternatively, the change may be performed without a separate
indication at a time point which is agreed upon with the BS so as
to have predetermined time intervals. The examples of the change
are not limited to the description.
[0132] More specifically, in order to implement the above-described
first method as an embodiment of the present invention, the
information element includes one or more pieces of reporting
configuration information to be applied to one or more TDD UL-DL
configurations. That is, one piece of reporting configuration
information, which is applicable to one or more TDD UL-DL
configurations, may exist, and the multiple pieces of reporting
configuration information may exist in association with the number
of multiple TDD UL-DL configurations. For example, I.sub.CQI/PMI
.sub._.sub.i or I.sub.RI.sub._.sub.i, which is one piece of
reporting configuration information, may be configured for each TDD
UL-DL configuration represented by i, a TDD UL-DL configuration may
be configured as a set represented by i, and
I.sub.CQI/PMI.sub._.sub.i or I.sub.RI.sub._.sub.i may be configured
which is reporting configuration information applied to the set
i.
[0133] Meanwhile, in the second method, reporting configuration
information may be reporting configuration information applied to a
DL-reference UL-DL configuration. In this case, the control unit
1020 may control the transmission unit 1030 such that the UE
transmits reporting by using a reporting periodicity and a
reporting offset of the reporting configuration information
corresponding to a DL-reference UL-DL configuration identified
based on the TDD UL-DL configuration. For example, when a TDD UL-DL
configuration of an SCell is 2, a TDD UL-DL configuration of a
PCell is 2, and the UL-DL configuration of the SCell and that of
the PCell correspond to set 1, if Table 5 is applied, a
DL-reference UL-DL configuration is 2. The UE transmits reporting
by using a reporting periodicity and a reporting offset which are
indicated by I.sub.CQI/PMI or I.sub.RI which is reporting
configuration information corresponding to a configuration of
2.
[0134] A method which uses the reporting configuration information
of the DL-reference UL-DL configuration may be applied to all of
the radio frames or may be applied to only a boundary radio frame,
as described above with reference to FIG. 5. In this case, the
control unit 1020 may control the transmission unit 1030 to
transmit reporting by using a reporting periodicity and a reporting
offset of the reporting configuration information corresponding to
a DL-reference UL-DL configuration identified based on the TDD
UL-DL configuration in the boundary radio frame.
[0135] Also, a DL-reference UL-DL configuration may be selected
according to the implicit or fixed scheme as described in the 2-2
case. In this case, the control unit 1020 controls the transmission
unit 1030 such that the UE transmits reporting according to
reporting configuration information determined according to TDD
UL-DL configurations before and after the change. The determined
reporting configuration information is configured according to the
implicit or fixed scheme between the BS and the UE, and thus a
DL-reference UL-DL configuration, to which the reporting
configuration information is to be applied, may be predetermined in
a network design process, or may be predetermined in such a manner
that the BS possesses various selection items and signals a
particular selection item to UEs.
[0136] The above-described reporting configuration information may
be transmitted according to a scheme shown in Table 6. In Table 6,
"cqi-pmi-ConfigIndex" or "ri-ConfigIndex" may increase according to
the number of TDD UL-DL configurations or DL-reference UL-DL
configurations, or the number of sets of UL-DL configurations or
DL-reference UL-DL configurations. The reconfiguration of a
configuration of CQI-ReportPeriodic in a case where K pieces of
reporting configuration information are configured is illustrated
in FIGS. 11 and 12. A configuration example described below may be
an embodiment of the present invention, and when TDD UL-DLs are
determined as a set differently from the configuration example,
reporting configuration information may be separately combined to
the relevant set.
[0137] FIGS. 11 and 12 are views each illustrating a configuration
example of a CQI-ReportPeriodic according to an embodiment of the
present invention.
[0138] Referring to FIG. 11, "cqi-pmi-ConfigIndexes" or
"ri-ConfigIndexes" to be applied to a k number of UL-DL
configurations are included in a configuration example of
CQI-ReportPeriodic as indicated by reference numerals 1110 and
1120. k signifies a maximum number which may be set, and
cqi-pmi-ConfigIndex_0, cqi-pmi-ConfigIndex_1, . . . ,
cqi-pmi-ConfigIndex_k represent I.sub.CQI/PMI .sub._.sub.0,
I.sub.CQI/PMI .sub._.sub.1, . . . , I.sub.CQI/PMI.sub._.sub.k,
respectively. ri-ConfigIndex_0, ri-ConfigIndex_1, . . . ,
ri-ConfigIndex_k represent I.sub.RI.sub._.sub.0,
I.sub.RI.sub._.sub.1, . . . , I.sub.RI.sub._.sub.k,
respectively.
[0139] Referring to FIG. 12, REPORT_ConfigType for each of a k
number of report configurations is defined as indicated by
reference numeral 1230, and the types indicate multiple pieces of
reporting configuration information as indicated by reference
numerals 1210 and 1220. As a result, values of I.sub.CQI/PMI
.sub._.sub.0, I.sub.CQI/PMI .sub._.sub.1, . . . ,
I.sub.CQI/PMI.sub._.sub.k configure cqi-pmi-ConfigIndex_r12, and
values of I.sub.RI.sub._.sub.0, I.sub.RI.sub._.sub.1, . . . ,
I.sub.RI.sub._.sub.k configure ri-ConfigIndex_r12.
[0140] The embodiments of the present invention relates to the
periodic CQI/PMI reporting method and the apparatus for the same,
which are more adaptive between the UE, for which an eIMTA
technique is configured, and the BS. The method and the apparatus
allow periodic CQI/PMI reporting to be supported in eIMTA for
controlling interference between the BSs and adaptive traffic in an
LTE TDD system. When the present invention is applied, periodic
CQI/PMI reporting, which is based on an RRC configuration, can be
performed according to a dynamically-changed TDD UL-DL
configuration. Specifically, when the above-described BS and UE are
implemented, periodic CQI/PMI reporting, which is more adaptive and
appropriate, can be smoothly performed according to a
dynamically-changed TDD UL-DL configuration.
[0141] Although a preferred embodiment of the present invention has
been described for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying claims.
Therefore, the embodiments disclosed in the present invention are
intended to illustrate the scope of the technical idea of the
present invention, and the scope of the present invention is not
limited by the embodiment. The scope of the present invention shall
be construed on the basis of the accompanying claims in such a
manner that all of the technical ideas included within the scope
equivalent to the claims belong to the present invention.
* * * * *